Hydrofining-hydrocracking process employing special alumina base catalysts



United States Patent ()fiice 3,340,180 Patented Sept. 5, 1967 3,340,180HYDROFINING-HYDROCRACKING PROC- ESS EMPLOYING SPECIAL ALUMINA BASECATALYSTS Harold Beuther, Gibsonia, and Stephen L. Peake and Bruce K.Schmid, Pittsburgh, Pa., assignors to Gulf Research & DevelopmentCompany, Pittsburgh, Pa., a corporation of Delaware No Drawing. FiledAug. 25, 1964, Ser. No. 392,049 20 Claims. (Cl. 208-108) Our inventionrelates to the hydrogen treatment of heavy pertoleum hydrocarbons andderviatives or fractions thereof and in particular relates to theremoval of sulfur and nitrogen compounds therefrom and to thehydrocracking thereof.

These heavy petroleum hydrocarbons are available commercially inconsiderable abundance but they are of relatively low value. In manyinstances such heavy petroleum hydrocarbons are employed as low-gradefuels without further treatment. This, at best, results in a-poor returnto the producer and the return is being further reduced since manyjurisdictions have adopted regulations restricting the amount of sulfurcontaining material that can be present in fuels burned within theirboundaries, thereby requiring removal of substantial quantities ofsulfurfrom these hydrocarbons, such as residuals, prior to sale. It haspreviously been suggested that sulfur be removed from residual fractionsand other heavy petroleum hydrocarbons by subjecting the heavyhydrocarbon to treatment with hydrogen in the presence of hydrogenationcatalysts. These suggested procedures, however, entail the employment ofexpensive operating conditions such as, for example, unusually highpressures, i.e., at least 2000 p.s.i. Previous attempts to remove sulfurfrom residual stocks by hydrogenation at moderate pressures haveresulted in extremely rapid deactivation of the catalysts by metal andcoke deposition on the catalysts due to the metalliferous and asphalticcontaminants contained in such stocks. Further, the previous attemptshave resulted in an unsatisfactorily low degree of desulfurization.Similarly, attempts to enhance the value of these heavy petroleumhydrocarbons by removal of nitrogen through bydrogenation have beenconfronted with the same problems.

An alternative course which has been proposed as a means of enhancingthe value ofthese heavy petroleum hydrocarbons is to hydrocrack suchstocks in order to produce'more valuable, lower-boiling fractions. Toeffect hydrocracking of'heavy hydrocarbons, it is necessary to employ acatalyst which is extremely active in the presence of asphaltic andmetalliferous contaminants and which has extremely good agingcharacteristics, i.e., maintains its cracking activity for long periodsof time while exposed to largequantities of asphaltic materials. Suchcharacteristics are not necessarily required when hydrocracking lighterstocks such as, for example, a middle distillate fraction. As mentionedabove, however, metal impurities in the stocks to-be treated cause rapiddeterioration of the activity of the catalysts, and the coking of thecatalysts due to the presence of asphaltics in the stocks also has astrong deactivating eflFect. Thus, a commercially acceptablehydrocracking process for heavy petroleum hydrocarbons requires not onlythe employment of an extremely active catalyst in the presence ofasphaltic and metalliferrous contaminants but also the employment of acatalyst and operating conditions which provide good catalyst aging.

It is an object of our invention to provide improved procedure for thehydrogen treatment of heavy petroleum hydrocarbons.

Another object ofour invention is to provide improved procedure for theremoval or reduction of sulfur and/or nitrogen compounds from heavypetroleum hydrocarbons by catalytic hydrogen treatment.

A further object of our invention is to provide improved procedure forhydrodesulfurization of heavy petroleum hydrocarbons employing moderatepressures, e.g., below about 2000 psi.

Another object is to provide improved procedure for hydrocracking heavypetroleum hydrocarbons, particularly a procedure which enables highconversion into lower boiling materials.

These and other objects areaccomplished by our invention which includestreating a heavy petroleum hydrocarbon with hydrogen in the presence ofa catalyst comprising essentially a minor amount of a hydrogenationcatalyst composited with a major amount of an activated alumina havingless than 5 percent of its pore volume that is in the form of poreshaving a radium of 0 to 300 A. in pores larger than 100 A. radius andhaving less than 10 percent of said pore volume in pores larger than A.radius. This activated alumina is prepared by treating a substance whichis predominantly composed of a crystalline alumina hydrate containingfrom 1.2 to 2.6 mols of water of hydration and which is substantiallyfree of alumina monohydrate and alumina trihydrate; the alumina hydratebeing prepared by precipitation from a solution of an aluminum compoundat a pH between 7 and 12, and drying to the above-mentioned water ofhydration content prior to substantial transformation to an aluminahydrate having a higher or lower water of hydration content. The driedalumina hydrate is then hydrothermally treated by heating it in thepresence of water in an autoclave at a temperature sufiicient tovaporize the water and under the pressure generated in the autoclave atthe temperature. This is followed by drying and calcining thehydrothermally treated alumina hydrate to provide the activated alumina.

The heavy petroleum hydrocarbons treated in accordance with ourinvention contain sulfur, asphaltic and metalliferous compounds ascontaminants, contain substantial amounts of hydrocarbon componentsboiling above 300 F., and contain residual materials. As employed hereinthe term residual materials means the undistilled petroleum fractioncontaining the highest boiling components of the crude. There are manynatural petroleum hydrocarbons of a heavy nature containing residualmaterials and containing the contaminants mentioned. All such stocks canbe treated in accordance with ourinvention. Also many petroleumhydrocarbons yield residual fractions on distillation under reduced oratmospheric preS- sures, which fractions contain the contaminantsmentioned. Examples of such stocks are reduced and topped crudes. Ourinvention is applicable to the treatment of all such residual fractions.Further, our invention is particularly useful in the treatment ofpetroleum fractions boiling in the range above about 700 F. and evenabove 1000 F.

Broadly, the. operating conditions employed in the practice of ourinvention include a hydrogen pressure from about 300 to about 3000p.s.i., a space velocity from about 0.1 to about 10.0 volumes of heavyhydrocarbon per volume of catalyst per hour, a hydrogen feed rate fromabout 2000 to about 30,000 standard cubic feet per barrel of chargestock (s.c.f./b.), a hydrogen consumption rate from about 1 to about 30or 40 mols of hydrogen per atom of sulfur removed from thechar-ge stockand a temperature from about 700 to about 900 F. The pressures mentionedthroughout the specification and in the claims are to be construed ashydrogen partial pressures whether specifically so stated in eachinstance or not. The temperatures mentioned herein and in the claims areaverage reactor temperatures since the difference between inlet andoutlet temperatures can differ as much as'30 F. and even more dependingupon the charge stock and the severity of other operating conditions.

As indicated, the activated alumina carrier or support employed in theprocess of our invention is obtained by drying and calcining an aluminahydrate derived from the hydrothermal treatment of a materialpredominantly composed of a crystalline alumina hydrate containing from1.2 to 2.6 mols of water of hydration and which is substantially free ofalumina monohydrate and alumina trihydrate. Any aluminum salt may beemployed in preparing this alumina hydrate containing 1.2 to 2.6 mols ofwater of hydration. For instance aluminum nitrate, chloride, acetate,formate, fluoride, sulfate, and other salts of aluminum may be used.Also a variety of bases such as sodium hydroxide, ammonium hydroxide,potassium hy-.

droxide, etc. may be employed to precipitate the alumina hydrate.However, it is preferred to employ salts of aluminum and bases which donot give reaction byproducts or salts which are difficult to separatefrom the desired alumina hydrate. For instance, if aluminum sulfate and/or sodium hydroxide are employed or even if aluminum sulfate andammonium hydroxide are employed, sulfate salts are formed which aredifiicult to remove by water wash ing and usually require prolongedwater washing for complete removal. On the other hand, if aluminumnitrate, aluminum chloride or an aluminum salt of an organic acid isused and a base such as ammonium hydroxide is employed, the salts whichare formed are readily soluble in water and can be easily removed bywater washing of the alumina hydrate. For the above reasons potassiumand sodium hydroxide are considered to be of little value as comparedwith aqueous ammonia. Regardless of the specific aluminum salt and basethat are used, the final product should be substantially free of suchsalts. Because of ease in removing salts it is preferred to use aluminumnitrate or chloride and neutralize with ammonium hydroxide.

The utilization of a pH between 7 and 12 is essential in order to obtainthe particular alumina hydrate utilized to obtain the catalyst supportemployed in the process of our invention. In other words, the use of apH above or below this range results in formation of large amounts ofundesirable alumina hydrates containing higher and/or lower quantitiesof water of hydration than 1.2 to 2.6 mols per mol of A1 0 Also, caremust be employed at all times during the neutralization to avoid alocalized higher or lower pH. If a local pH above or below this valueexists at any time, a less satisfactory form of alumina hydrate having adifferent water of hydration content will be formed in this localregion. This less satisfactory form will dilute the desired form andwill reduce its value to a degree greater than to be expected from theamount which is present. For this reason, it is desirable to utilize abasic solution having the desired pH between 7 and 12 and to add thealuminum salt in small amounts, preferably an aqueous solution thereof,to the basic solution with rapid agitation. If this expedient is used,the resultant alumina hydrate is unlikely to be precipitated even inlocal regions at a pH below 7 or greater than 12. A pH of 7-8.5 isadvantageous since in many cases it gives a higher yield and a moreactive product. Stoichiometric amounts of the aluminum salt and base areadvantageously used. It is also preferred to use solutions of both baseand aluminum salt which are either dilute or of moderate concentration,such as between about one and percent aluminum salt and between aboutone and 20 percent of basic solution. However, higher or lowerconcentrations can be used. The alumina hydrate thus formed is separated from the aqueous mixture by filtration, centrifuging, decanting,or any other suitable method. Washing to remove salts as described aboveis advantageous and is necessary if the salt is not readily volatilizedduring the subsequent treatment.

This separated alumina hydrate still contains entrained, adherent ormechanically held water, and it must be dried to remove this waterbefore a stable product is obtained. Even though the desired form ofalumina hydrate is initially prepared, it is unstable and may undergotransformation during the process of precipitation, separation and/ ordrying and it is necessary to observe certain precautions to avoid thisharmful transformation. Therefore, before giV- ing details on the dryingprocedure, it would be best to consider procedures which may be employedto avoid this harmful transformation, particularly during the process ofneutralization and precipitation.

One method for avoiding this harmful transformation is to use elevatedtemperatures such as above about F. These elevated temperatures reduceor prevent the undesirable transformation of the alumina hydrate intoone hav; ing a lower or higher water of hydration content. However, forthese temperatures to have these beneficial effects, they should bemaintained throughout the above mentioned precipitation and washingsteps and until the drying is completed. Generally, the temperatureshould be kept as close to 170 F. as is convenient but if a temperaturein the range of 200 F. or slightly above is employed, the residence timeshould be reduced accordingly. This specific mode of preparing aluminahydrate of 1.2 to 2.6 mols of water of hydration content is the subjectof U.S. application Serial No. 118,240, filed June 20, 1961, in thenames of W. L. Kehl and M. M. Stewart, now U.S. Patent No. 3,188,174.

According to another method of avoiding the transformation into lessdesirable forms the precipitation and drying are carried out withpromptness. Thus the time required for the transformation to take placeis such that the entire precipitating and drying operations can becarried out even with relatively large or commercial quantities if careis taken to do so expeditiously. Ordinarily formation and drying shouldtake place within a period of at most 24 hours and preferably withinabout 4 to 8 hours or less when this expedient is used. It is especiallyadvantageous to use a pH of 78.5 in connection with this particularmethod.

The undesirable transformation can be avoided by other methods ofpreparation. For instance, the presence of acetate ion greatly delaysthe transformation even at ordinary temperatures. Also bufferedprecipitating solutions may be used. These expedients are the subjectmatter of applications S.N. 118,279, filed June 20, 1961 and S.N.118,241, filed June 20, 1961, in the names of W. L. Kehl and M. M.Stewart, now U.S. Patents Nos. 3,151,940 and 3,151,939, respectively;

The drying of the alumina hydrate may be carried out in any desiredmanner so long as it is completed prior to the harmful transformation.As may be gathered from the above described procedures for avoiding thetransformation, a temperature of above 170 F. will prevent thetransformation from taking place. Therefore it is advantageous to employtemperatures at least ashigh as this for drying. The drying may becarried out in vacuum if desired. It, of course, follows thatconsiderably higher temperatures than 170 F. may be employed. Forinstance, it is entirely satisfactory to utilize temperatures such as212 F. or even 250 F. This drying removes the mechanically held waterand yields a stable product. It is predominantly composed of the desiredcrystalline alumina hydrate containing 1.2 to 2.6 mols of water ofhydration and is substantially free of alumina monohydrate and aluminatrihydrate.

After drying, this alumina hydrate is subjected to hydrothermaltreatment by placing the alumina hydrate together with water in a sealedvessel, such as an autoclave, and heating at an elevated temperature fora period of time. Generally, the quantity of water employed issuflicient to immerse completely the dried alumina hydrate. The sealedvessel is then heated so as to raise the temperature gradually over aperiod of time, suchas,

for example, about 2 to 8 hours, and the temperature is then maintainedat an elevated level from about 225 or 250 F. up to about 500 F. or 700F., in any event a temperature adequate to provide sufiicient watervapor pressure to prevent dehydration of the alumina hydrate, for aperiod from a few minutes up to several hours, for example, from 2 or 3minutes up to 8 or 16 hours. It has been found that the roles of timeand temperature in the hydrothermal treatment are to a considerableexten interchangeable. Thus, one might by suitably extending theduration of treatment produce the desired conversion at a lowtemperature which would be essentially the same as that obtained in ashorter period of time employing a higher temperature. For example,employing a temperature of 250300 F. for a period of 4 hours is usuallysufiicient to bring about substantially complete conversion, Whiletreatment at a lower temperature for the same period of time eflFects apartial conversion and yet treatment at a lower temperature for a longerperiod can usually effect substantially complete conversion.Accordingly, by gradually raising the temperature of the autoclave fromroom temperature up to about 325 F. over a period of 4 hours and thenmaintaining the temperature at that level for an additional four hours,resulting in a total processing time of 8 hours, substantially completeconversion can be effected. A certain degree of caution, however, mustbe exercised, since the employment of too high a temperature for aparticular length of time of treatment will destroy the desired uniquepore structure of the product. For example, the employment of atemperature from about 250 F. up to about 325 or 350 F. for a period offour hours will produce an alumina hydrate which upon calcinationprovides an alumina having the necessary pore size distribution of lessthan 5 percent of the pore volume in pores larger than 100 A. and lessthan 10 percent of the pore volume in pores larger than 80 A., while theemployment of a temperature much above about 350 F. results in a finalalumina having a pore size distribution somewhat outside this range. Thetemployment of a temperature of 400 F. for a treatment period of fourhours so completely destroys the structure that an alumina is obtainedhaving about 30 percent of the pores larger than 100 A. and about 50percent of the pores larger than 80 A. It is believed that the heatingpermits the metastable dried alumina hydrate which is hydrothermallytreated to rearrange to a stable form of alumina hydrate while the Waterpressure prevents dehydration of the alumina hydrate to alumina.Accordingly, we believe that any water vapor pressure above thedehydration pressure of the dried alumina hydrate at the particulartemperature selected is adequate for the hydrothermal treatment. It ispreferred, however, to employ an excess of pressure obtained byemploying a quantity of water in excess of the minimum required as asafety precaution, thereby insuring that the minimum required watervapor pressure is present. Generally, the pressure will be in the rangefrom about 30 to about 700 p.s.i.g., although it can vary from a low of10 p.s.i.g. at 200 F. to a high of 3100 p.s.i.g. at 700 F. Theemployment of a slight excess of Water vapor pressure in thehydrothermal processing of our invention has no deleterious effects uponthe conversion or the product hydrothermally treated alumina hydrate.

The hydrothermally treated alumina hydrate is substantially amonohydrate which can be described as a less well crystallized boehmitehaving crystallites of an extremely small diameter. Thus, commerciallyavailable boehmites and boehmites obtained, for instance, bybydrothermal treatment of a trihydrate have an average crystallitediameter in the range from about 1200 or 1300 A. up to about 2000 A. orabove, While the average crystallite diameter of the hydrothermallytreated alumina hydrate described herein is about 100 A.

At the completion of this treatment the hydrothermally treated aluminahydrate is then dried and calcined to obtain the activated alumina whichconstitutes the carrier for the catalyst employed in our invention. Anyconventional method heretofore used for calcining a dried alumina can beemployed. However, a temperature above about 1600 F. should not be usedsince such elevated temperatures cause deactivation of the activatedalumina. A temperature of between about 800 F. and 1200 F. ordinarily issatisfactory. A calcining time of between about 2 and 24 hoursordinarily will be satisfactory. In most cases the shorter time periodswill be used with the higher temperatures and the longer periods withthe lower temperatures. The final product is opaque, hard and glassy. Ithas a unique pore structure and is A1 0 which still contains a smallamount of water-usually less than about 3 percent. 7

This unique pore structure of the alumina used in our process can becharacterized as including a substantial, usually a predominant, portionof the total pores and consisting of pores less than 300 A. radiushaving the particular pore size distribution described previously. Forexample, a similar alumina has been found to be composed almost entirelyof pores less than 300 A. radius, which pores comprise more than percentof the total pore volume.

In the practice of our invention we employ the activated aluminadescribed above as the catalyst support rather than a commercialalumina-containing silica support inasmuch as it provides the desiredactivity but does not possess the extremely high initial activity ofcommercial silica-alumina supports and, therefore, does not causeextremely high initial cracking which in turn causes rapid coking of thecatalyst.

Surprisingly, we have found that when this activated alumina iscomposited with suitable metals having catalytic activity, a catalystcomposition is obtained which yields unexpectedly superior results inthe hydrocracking and hydrodesulfurization of heavy petroleumhydrocarbons. Such activity is particularly unexpected in light of thefact that, When the alumina described above is substituted forcommercially available aluminas of a different type in certain otherhydrocarbon treatment processes, e.g., hydroreforming, the resultsachieved are no better than and, in some instances, even inferior to theresults obtained employing the commercial supports.

The activated alumina carrier described above is composited with ametalliferous hydrogenating component. Any of the conventionalprocedures for preparation of such a two-component catalyst may be used.Ordinarily we prefer to impregnate the activated alumina carrier with anaqueous solution of a salt of the metalliferous hydrogenating catalystand then dry and calcine to obtain the finished hydrogenation catalyst.Any hydrogenating component such as Group VIII or Group VI metal oxidesor sulfides, such as molybdenum or tungsten oxides and sulfides ornickel or cobalt metals, oxides or sulfides may be used. It isfrequently desirable to employ mixtures of these catalysts such ascobalt-molybdenum, nickelcobalt-molybdenum, nickel-tungsten, etc., theiroxides or sulfides. A particularly desirable catalyst is a mixture ofoxides of nickel, cobalt and molybdenum such as described in U.S. Patent2,880,171, March 31, 9, Flinn .et al.

In one aspect our invention relates to the desulfurization of heavypetroleum hydrocarbons. When operating in accordance with this aspect ofour invention, the contacting of the charge stock with hydrogen iscarried out under conditions of temperature and space velocity whichavoid substantial or extensive cracking of carbon-to-carbon bonds. Wehave found that by operating in accordance with this procedure moderatehydrogen partial pressures of between about 300 and 2000 p.s.i. can beemployed yet nevertheless long onstream periods or high throughputs maybe used to give extensive desulfurization. This procedure not onlyresults in improved removal of sulfur compounds but also in an improvedremoval of 700 to about 875 F. and preferably between about .750

and 850 F. are employed. By employing temperatures within these rangesis meant to commence operation at the lower end of the temperature rangeand gradually increase the temperature during the course of operation inorder to maintain the rate of desulfurization or the sulfur content ofthe product constant until a terminal temperature is reached, at whichtime the reactor is shut down and the catalyst regenerated. Thus, forexample, the hydrodesulfurization process can be commenced at a temperature within the range from about 700 to 800 F. and the temperatureincreased incrementally until a temperature in the range of about 775 to875 F. is attained, preferably the process can be commenced at atemperature of about 750 to 775 F. and the temperature increasedgradually until a temperature of about 800 to 850 F. is attained at theend of the run.

Also when practicing this aspect of our invention a pressure betweenabout 300 and 2000 p.s.i. and preferably between 1000 and 1500 p.s.i. isused, a space velocity between about 0.10 and 10.0 and preferablybetween 0.2 and 3.0 can be used, a hydrogen feed rate from about 5000 toabout 30,000 s.c.f./ b. and preferably from about 4000 to about 10,000s.c.f./b is employed, and a hydrogen consumption of about 1 to aboutmols of hydrogen per atom of sulfur removed from the charge stock andpreferably from about 2 to about 5 mols of hydrogen per atom of sulfuris employed. While hydrodesulfun'zation causes the formation of lowerboiling materials due to the rupture of the sulfur bonds in thehydrocarbon molecule, this type of rupturing does not cause depositionof coke on the catalyst and is desirable. Since the process of thisaspect of our invention results in extensive rupturing of sulfur bonds,there will be lower boiling hydrocarbons formed as a byproduct and thesehydrocarbons have desirable properties as compared with the residualmaterial being treated. Since the objective is the utilization of aslong an onstream period as possible, it is best to use conditions whichavoid carbon-to-carbon cracking inasmuch as this results in depositionof coke on the catalyst and this in turn increases the rate ofdeactivation of the catalyst. Therefore, this cracking should bemaintained below about 20 percent formation of volatile material overand above that formed by rupturing of sulfur bonds. The space velocityand temperature can be regulated to give the desired mild conditions'which avoid extensive carbon-to-carbon cracking. Thus,

with a given catalyst the higher the temperature and the lower the spacevelocity the higher will be the amount of carbon-to-carbon crackingwhereas the reverse conditions utilizing a lower temperature in therange given and a higher space velocity will reduce the carbon-to-carboncracking. If this carbon-to-carbon cracking is kept below the abovementioned maximum value, the reaction may be continued for relativelylong periods of time on the order of 3 to 75 barrels of residual feedstock per pound of catalyst. Eventually the catalyst will requireregeneration and this is accomplished in the usual fashion byterminating the onstream reaction and burning the carbonaceous materialfrom the catalyst by combustionregeneration. The regenerated catalystthen may be reused in the process.

Of the catalysts mentioned above it is preferred to utilize a catalystof the cobalt molybdate type in practicing this aspect of our inventionsince such catalyst has a high deculfurization activity and a lowactivity for carbon-to-carbon splitting. As mentioned above, aparticularly desirable catalyst of this type is a mixture of the oxidesof nickel,'cobalt and-molybdenum as described in US. Patent 2,880,171.Other nickel-cobalt-molybde num catalysts in which the total metalcontent isrless than about 20 to 25 percent by weight of the catalystand in which the atomic ratio of Group VIII to Group VI metals isgreater than 1.0 can also'be employed. with equally satisfactoryresults.

Another aspect of our invention relates to the hydrocracking of heavypetroleum hydrocarbons. When operat-' ing in accordance with this aspectof our invention the heavy hydrocarbon is contacted with hydrogen underhydrocracking conditions of temperature and pressure in.

the presence of a two-component catalyst. The hydrogenating component ofthis catalyst comprises a Group VI metal together with a Group VIIImetal or their oxides or sulfides. Thus, for example, mixtures of thesecomponents such as nickel-cobalt-molybdenum, cobalt-molybdenum,nickel-molybdenum, nickel-tungsten, etc. and their oxides and sulfidescan be employed. The support for the hydrogenating component is theactivated alumina described above. The activated alumina is compositedwith the hydrogenating component in accord ance with any of theconventional procedures for impregnation of porous carriers withmulti-component catalystsl Ordinarily we prefer to impregnate theactivated alumina carrier with an aqueous solution of a salt of a GroupVI metal such as molybdenum followed by drying and calcining and then toimpregnate with an aqueous salt of a Group VIII metal such as nickel orcobalt followed by a second drying and calcining. If desired the oxidesof the metal components can be reduced or partially reduced by treatmentwith hydrogen prior to employment in our process. In the event a sulfideis to be present, the 'catalyst can be treated with hydrogen sulfide toform the metal sulfides. This is advantageously carried out by treatingwith a mixture of hydrogen and hydrogen sulfide at a temperature betweenabout 450 and 950 F. Also the metal components can be reduced and/ orsulfided by contacting with the feed stock. Alternatively, the catalystmay be formed by precipitating the sulfides of the metals in aqueousimpregnating solutions as by treatment with hydrogen sulfide.

In accordance with this aspect of our invention the heavy hydrocarbon tobe hydrocracked is contacted with the above described catalyst at atemperature between about 750 and 900 F. and preferably between '780 and875 F. By employing temperatures within these ranges is meant tocommence operation at the lower end of the temperature range andgradually increase the temperatureduring the course of operation until aterminal temperature is reached, at which time the reactor is shut downand the catalyst regenerated. Thus, for example, the hydrocrackingprocess can be commenced at a temperahire within the range from about750 to about 850 F. and the temperature increased incrementally untilthe temperature range of about 810 to about 900 F.is attained, at whichpoint the run is terminated. Preferably the process can be commenced ata temperature within the range from about 780 to about 810 F. and thenincreased incrementally until a temperature in the range from about 840to about 875 F. is attained. The temperature is increased during thecourse of the process from the lower starting range at a rate suflicientto maintain the volume of distillate yield at a predeterminedsatisfactory level and this gradual increase of'temperature is continueduntil such time as the upper limit of the temperature range has beenachieved.

When operating in accordance with this aspect of our invention ahydrogen partial pressure between about 1500 and 3000 p.s.i., preferablybetween about 2000 and 2500 p.s.i., a space velocity from about 0.1 to5.0, preferably from about 0.2 to 2.0, a hydrogen feed rate from about5000 to about 30,000 -s.c.f./b. and preferably from about 7,000 to about20,000 s.c.f./b. and a hydrogen consumption rate from about 6 to about40 mols of hydrogen per atom of sulfur removed from the charge stock,preferably from 6 to 20 mols of hydrogen per atom of sulfur, can beemployed.

The characteristics of the products obtained from the practice of thisaspect of our invention will depend upon the feed stock, particularlythe boiling point of the feed stock, and the reaction conditionsemployed. Thus, it is possible to produce a furnace oil product which isusable directly from the processing unit. Furthermore, this aspect ofour invention can also be employed to produce a low octane gasolinedirectly from residual stocks. In the practice of this aspect of ourinvention, it is also possible to recycle to the reactor all portions ofthe product boiling above a particular range, such as, for example, thegas oil range (1050 F.), thereby increasing the net yield of usableproducts per volume of heavy hydrocarbons charged.

As mentioned previously, the pore size distribution of the activatedalumina employed in our invention in the areas of both hydrocracking andhydrodesulfurization of heavy petroleum hydrocarbons yields unexpectedlysuperior results. It is theorized that these unexpectedly superiorresults are due principally to the extremely small pore size of thesupport. As is well known in the art, heavy petroleum hydrocarbons, suchas residual stocks, for example, contain large quantities of asphalticand metalliferous materials and that the presence of such contaminantsadversely affects catalyst life; the asphaltics by depositing coke onthe catalyst and the metalliferous materials by depositing metals on thecatalyst surface thereby poisoning the catalyst. As is also well known,the asphaltic compounds are polyaromatic molecules of comparativelylarge size and the metals present in petroleum stocks are normallycontained in the form of extremely large molecules. We believe that themechanics of the hydrocracking and hydrodesulfurization aspects of ourinvention are such that, since a substantial portion of the surface areaof the catalyst is within the extremely small pores of the catalyst, agreat number of the extremely large molecules present in the stock areprevented from entering the small pores where they might be adsorbed onthe catalyst surface and react. Thus, the particular type of activatedalumina described above when employed in our invention permit only alimited amount of the large molecular asphaltic and metalliferousmaterials to react while providing an active catalyst of high surfacearea suitable for adsorbing the comparatively smaller hydrocarbonmolecules and permitting them to react. It is believed, therefore, thatminimizing the reaction of the asphaltic and metalliferous materials inthis manner also minimizes the coke and metal deposition on the surfaceof the catalyst without any reduction in the desired reactions. Acomparison of the products obtained in accordance with our inventionwith those obtained by known processes tends to substantiate thistheory, inasmuch as the products of our process have a higher metalscontent and contain more higher boiling asphaltics. We believe,therefore, that this theory accounts for the unique coaction of theparticular activated alumina described above with heavy petroleumhydrocarbons in accordance with our invention.

In order to illustrate our invention in greater detail, reference ismade to the following examples:

Example I A 4730 gram quantity of aluminum chloride (AlCl -6H O) wasdissolved in 20 liters of water and 500 grams of glacial acetic acid wasthen added to the solution. In another vessel 2000 milliliters ofammonium hydroxide (28% NH was mixed with 5000 milliliters of water, and

this solution was then added to the aluminum chloride solution until apH of 8 was obtained. The slurry formed from mixing the two solutionswas filtered and washed on the cake until the conductivity of the washwater lined out indicating that the washing was complete. The wet filtercake was then dried at 250 F. for 16 hours to provide an alumina hydratecontaining from 1.2 to 2.6 mols of water of hydration. A 500 gram sampleof the alumina hydrate was charged to an autoclave with 500 millilitersof distilled water and heated to 350 F. in four hours and maintained atthat temperature for an additional four hours under the pressuregenerated by the water. The material from the autoclave was filtered andthe hydrothermally treated alumina hydrate was dried at 250 F., sized to10-20 mesh and calcined at 1000 F. for 16 hours to provide the aluminasupport.

An ammonium monomolybdate solution was prepared by dissolving 33.6 gramsof ammonium paramolybdate [(NH Mo O -4H O] in distilled water and 15milliliters of ammonia (28% NH and diluting to 130.5 milliliters withdistilled water. The final solution weighed 156.8 grams and contained11.5 percent molybdenum. This solution was added with stirring to anevaporating dish which contained 196.4 grams of the alumina supportdescribed above. The solution completely wet the alumina support(incipient wetness-0.665 milliliters of solution per gram) and left noexcess solution in the dish. The wet material was dried at about 250 F.for 24 hours.

A nickel nitrate-cobalt nitrate solution was prepared by dissolving 4.4grams of nickel nitrate (NiNo -6H O) and 11.6 grams of cobalt nitrate[Co(NO -6H O] in distilled water and diluting to 108 milliliters. Thefinal solution weighed 121.0 grams and contained 0.94 percent nickel and1.88 percent cobalt. This solution was then added with stirring to anevaporating dish containing 228.8 grams of the dried material from themolybdenum impregnation above. The solution completely wet themolybdenum impregnated material (incipient wetness 0.473 milliliters ofsolution per gram) and left no excess solution in the dish. Theresulting Wet mixture was dried at about 250 F. for 24 hours and thencalcined in air in an electric muflle furnace at 900 F. for about 10hours. The final metal content of the catalyst was about 0.5 percentnickel, 1.0 percent cobalt and 8.0 percent molybdenum.

To illustrate the process of our invention, a Kuwait vacuum residue (18percent by volume crude) containing sulfur, asphaltic and metalliferouscontaminants was subjected to hydrogen treatment in accordance with theprocess of our invention employing the nominal condition of 1000p.s.i.g., 750 F., 0.5 liquid hourly space velocity and 10,000 standardcubic feet of hydrogen per barrel of feed. In order to afford a basis ofcomparison for our invention with previously suggested procedures, twoseparate runs were carried out; one employing the catalyst required inour invention produced as described above and the other using a catalystcomprising the same metals composition stated above but employing acommercial alumina which is widely used in this country as a carrier forhydrogenation catalysts. The physical characteristics of the twodifferent aluminas, including pore size distribution, are shown in TableI below. The pore size distributions shown in Table I were determined bythe technique of nitrogen adsorption and desorption isotherms describedin the article by Ballou and Doolen in Analytical Chemistry, volume 32,page 532, April 1960. It will be noted that in the alumina employed inour invention les than 5 percent of the pore volume is in pores largerthan 100 A. radius and less than ten percent of the pore volume is inpores larger than A. radius, while the pore size distribution of thecommercial alumina is outside this range.

11 1 H TABLE I shown in the 24-104 hour period (column 3). 'Thus,'th'epercent desulfurization obtained during the period of 24 HydrothennalCommercial to 104 hours in accordance with our invention is 84.0 A110:A12 3 percent, While the run employing the commercial alumina 5 supportduring the period of 24-96 hours (column 5) surfflceareayM-ilg- 170 7Only provides a 66.2 percent desulfurization. The true Porevolume, cc./g0.37 p 0.47 d t I d b 11 pore 13111115 (WM), 8 55 a van ageous resu tsunexpecte ly PIOVl ed y t e process g eg sg i gff of our invention aremore clearly evidenced by a com- VOLinrange: p parisonof the percentdesulfurization obtained at 30, 200-300 A. radius 0.6 0.9 6 .mwoo kmdius2'2 89 10 0 and 90 hours. it will be noticed that the percent 3() 1()(]Au is 112 desulfurization obtained with the process of our mven- 60-80 A.radius" 28.6 211 5H0 Admins 1L 5 17' 0 tion (columns 2 and 3) decreasedonly 3.1 percent dur 40-50 A radius" 3 2 mg the period of -90 hours,while the percent desul- 30-4011 radius 16.1 13.8 2M0 A radius g 12912.8 furization obtained when employ ng thecommercral cat 15-2011 rad sL2 M 15 alyst decreased 13.4 percent durlng'a s1m1lar period. A gi g g8'8 g-g more dramatic illustration of this point is thatthe per- 100 A.radius 2,8 9, cent desulfurlzation obtained after 90 hours"operation in80 A'mdms accordance with our inventionis substantially superior to thepercent desulfurization obtained after only 30 The mspectlon data of theKuwait vacuum residue em- 20 hours operation employing the commercialcatalyst. This ployed as a'charge stock is shown 1n column 1 of Table isfurther emphasized by the deactivation rates shown for 11 f COIIIPPIS 2and 3 of Table 11 Sh0W h eXaCt catalyst in the process of our inventionas opposed to operating condit ons and the results obtamed during twothe commercial catalyst as shown at the bottom of Table. differentoperat ng periods of the run cmbodylng the 11. From these data it can beseen that the life of'the process of our 1nvent1on and employing thecatalyst recatalyst employed in our invention is about four times qurredin our mventron, whlle columns 4 and 5 show the th life, hi d i h h c il catalyst, opel'atmg condltlolls and the results Obtamfid d rmg two Itwill also be noted that the process of our invention diiferent periodsof operation in the run employing the provides a greater increaseofproduct gravity in degrees commercial alumina. API than is provided bythe process employing the com- TABLE .II

Run Interval, hours (Charge) 8-24 24-104 824 24-96 Operating conditions:7

Pressure, p.s.i.g 1, 000 1, 000 1, 000 Average temp, F. 750 749 751Hydrogen rate, s.c.f.lb 9, 600 10,000 10,400 Space velocity,vol./hr./vol 0.49 0.50 0. 48 Inspections:

Gravity, API 5. 5 17. 7 10. 7 16.3 14. 7 Viscosity, SUV, sec.:

100 F 2,237 3,349 4,255 7,411 130F 768 1, 019 1,296 2,001 Sulfur,percent 5. 0.80 0. 87 1. 40 1. 84 Nitrogen, percent 0.43 0.26 0. 31 0.34 0.37 Carbon residue, percent 23. 11 8.80 9.72 10. 54 12.83 Insol. inn-pentane 15. 14 4. 54 5. 59 3. 65 5. 34 Nickel, p.p.m 32 11.0 10.9 7.712.2 Vanadium, p.p.m 102 14. 5 20. 0 7. 9 16. 7 Desuliurization, percent85. 3 84. 0 74. 3 66. 2 Yield, percent by wt. of charge: Gases,

01-0, 1.2 0.9 0.8 Yield, percent by vol. of charge:

Gasoline (cl-400 F.) 4. 3 Light gas oil (400-070 F)..- 8.8 Heavy gas oil(em-1,000 F.) 20.7 670 F. residue 90. 6 1,000 E. residue 69. 9 Catalystdeposits: Carbon, percent by wt. 17. 9 Hydrogen consumption:

S.c.f. 520 Mols H /atom S removed 3. 3 Percent desulturization at:

30 hours 60 hours 90 hours- Deactivation Percent sulfur in product/100hours Percent desulfurization/IOO hours A comparison of the data setforth in Table II clearly demonstrates the superiority of the process ofour invention over a process operating under similar conditions butemploying a commercial alumina support. For example, it can be seen thatthe process of our invention provides a remarkable improvement ininitial sulfur removal during the period of 8 to 24 hours (column 2), asopposed to the amount of sulfur removed during-the comparable period butemploying a commercial alumina support (column 4). Furthermore, suchimproved sulfur removal is maintained during continued operation asrial. As state previously, we believe that the particular aluminaemployed in accordance with our invention permits a greater portion ofthe asphaltic and metalliferous contaminants to pass through the reactorbed unconverted inasmuch as these large molecular contaminants areprecluded from entering the smaller sized pores of the contaminants,thereby lowering coke deposit. This is even further substantiated by thelower coke deposition on the catalyst in the process of our invention asopposed to the quantity of coke deposited on the commercial aluminacatalyst.

Example 11 In this example the same residual stock used in Example I isemployed as the charge stock to a hydrodesulfurization process. Thecatalyst employed in this example is also the samenickel-cobalt-molybdenum catalyst supported on alumina derived from ahydrothermally treated alumina hydrate that was employed in Example 1.After completion of normal start-up procedures which include introducingthe charge stock to the reactor at a low temperature, usually well belowoperating temperatures, and then gradually increasing the temperatureover a period of time, usually about 6 to 8 hours, until a normaloperating temperature is reached, the run of this example is commencedat an initial operating temperature of 750 F. Throughout the duration ofthe run the other operating conditions are maintained constant at ahydrogen partial pressure of 1000 p.s.i.g., a LHSV of 0.8 and a hydrogenrecycle rate of 5000 s.c.f./b. The sulfur content of the total liquidproduct obtained initially is 1.0 percent by weight. During the courseof this run the temperature is increased at an average rate ofapproximately 0.75 F./day in order to maintain the level of sulfurcontent in the total product at 1.0 percent or below. This operation iscontinued until an operating temperature of 840 F. is achieved (about120 days of operation), at which time the operation is discontinued.During the course of this run the hydrogen consumption is about 4 molsof hydrogen per atom of sulfur removed from the charge stock.

Thus, when operating in accordance with the particular embodiment of ourinvention described immediately above, it will be seen that a processfor desulfurizing a heavy petroleum hydrocarbon while operating at a lowpressure is provided. Further, the gradual increase in the operatingtemperature, in this example 0.75 F./ day, provides a product with aconstant low sulfur content, i.e., 1.0 percent or less, while alsoproviding an unexpectedly long catalyst life.

Example 111 In this example the same residual stock used in Example I isemployed as the charge stock to a hydrocracking process. The catalystemployed in this example is also the same nickel-cobalt-molybdenumcatalyst supported on alumina derived from a hydrothermally treatedalumina hydrate that was used in Example 1. After completion of normalstart-up procedures, which include introducing the charge stock to thereactor at a low temperature, usually well below operating temperatures,and then gradually increasing the temperature over a period of time,usually about 6 to 8 hours, until a normal operating temperature isreached, the run of this example is commenced at an initial operatingtemperature of 790 F. Throughout the duration of the run the otheroperating conditions are maintained constant at a pressure of 2000p.s.i.g., a space velocity of 0.5 LHSV and a hydrogen recycle ratio of10,000 s.c.f./b. The initial conversion of the charge stock todistillate boiling at less than 1000 F. when employing the initialconditions is 65 percent by volume. During thecourse of this run thetemperature is increased at an average rate of approximately 075 F./dayin order to maintain the level of conversion at 65 percent by volume ofthe feed to distillate boiling at less than 1000 F. This operation iscontinued until an operating temperature of 880 F. is achieved, at whichtime the operation is discontinued. During the course of this run thehydrogen consumption is about 7 mols of hydrogen per atom of sulfurremoved from the charge stock. Further, the product of this 'run has asubstantially higher API gravity (about 20) than the charge stock. Theproduct also has a comparatively high metals content.

Thus, when operating in accordance with the particular embodiment of ourinvention described immediately above, it Will be seen that a processfor hydrocracking a heavy petroleum hydrocarbon while operating at a lowpressure is provided. Further, the gradual increase in the operatingtemperature, in this example 0.75 F./day, provides a constant level ofconversion, while also providing an unexpectedly long catalyst life.

We claim:

1. A process for hydrogen treatment of heavy petroleum hydrocarbonscontaining sulfur, asphaltic and metalliferous compounds ascontaminants, containing substantial amounts of hydrocarbon componentsboiling above 300 F. and containing residual materials, which processcomprises contacting the hydrocarbons with hydrogen at a pressure fromabout 300 to about 3000 p.s.i., a space velocity from about 0.1 to about10.0 volumes of heavy hydrocarbon per volume of catalyst per hour, ahydrogen consumption rate from about 1 to about 40 mols of hydrogen peratom of sulfur removed from the heavy hydrocarbons and at a temperaturefrom about 700 to about 900 F. in the presence of a catalyst comprisingessentially a minor amount of a hydrogenating catalyst composited with amajor amount of an activated alumina having less than 5 percent of itspore volume that is in the form of pores having a radius of 0 to 300 A.in pores larger than 100 A. radius and having less than 10 percent ofsaid pore volume in pores larger than A. radius which alumina isprepared by treating a substance which is predominantly composed of acrystalline alumina hydrate containing from 1.2 to 2.6 mols of water ofhydration and which is substantially free of alumina monohydrate andalumina trihydrate, said alumina hydrate being prepared by precipitationfrom a solution of an aluminum compound at a pH between 7 and 12, anddrying to the above specified water of hydration content prior tosubstantial transformation to an alumina hydrate having a higher orlower water of hydration content, said treating comprisinghydrothermally treating the dried alumina hydrate'by heating it in thepresence of water at a temperature sufiicient to vaporize the waterunder autogenous pressure, whereby the alumina hydrate is convertedsubstantially to a monohydrate and drying and calcining thehydrothennally treated alumina hydrate.

2. The process of claim 1 wherein the hydrogenating catalyst is selectedfrom the group consisting of Group VI metals, Group VIII metals, theiroxides and sulfides.

3. The process of claim 1 wherein the hydrogenation catalyst consistsessentially of the oxides of nickel, cobalt and molybdenum.

4. The process of claim 1 wherein the contacting temperature is fromabout 750 to about 875 F., the pressure is from about 1000 to about 2500p.s.i., the space velocity is from about 0.2 to about 3.0 volumes ofheavy hydrocarbon per volume of catalyst per hour and the hydrogen aturefrom about 700 to about 875 F., a pressure from about 300 to about 2000p.s.i., a space velocity from-about 0.1 to about 10.0 volumes of heavyhydrocarbon per volume of catalyst per hour and a hydrogen consumptionrate from 1 to about 5 mols of hydrogen per atom of sulfur removed fromthe heavy hydrocarbons in the presence of a catalyst comprisingessentially a minor amount of a hydrogenating catalyst composited with amajor amount of an activated alumina having less than 5 percent of itspore volume that is in the form of pores having a radius of to 300 A. inpores larger than 100 A radius and having less than 10 percent of saidpore volume in pores larger than 80 A. radius prepared by treating asubstance which is predominantly composed of a crystalline aluminahydrate containing from 1.2 to 2.6 mols of water of hydration and whichis substantially free of alumina monohydrate and alumina trihydrate,said alumina hydrate being prepared by precipitation from a solution ofan aluminum compound at a pH between about 7 and 12, and drying to theabove specified water of hydration content prior to substantialtransformation to an alumina hydrate having a higher or lower water ofhydration content, said treating comprising hydrothermally treating thedried alumina hydrate by heating it in the presence of water at atemperature sufficient to vaporize the water under autogenous pressure,whereby the alumina hydrate is converted substantially to a monohydrateand drying and calcining the hydrothermally treated alumina hydrate.

6. The process of claim wherein the contacting temperature is from about750 to about 850 F., the pressure is from about 1000 to about 1500p.s.i., the space velocity is from about 0.2 to about 3.0 volumes ofheavy hydrocarbon per volume of catalyst per hour and the hydrogenconsumption rate is from about 2 to about 5 mols of hydrogen per atom ofsulfur removed from the heavy hydrocarbons. V

7. The process of claim 5 wherein the hydrogenating catalyst is selectedfrom'the group consisting of Group VI metals, Group VIII metals, theiroxides and sulfides.

8. The process of claim 5 wherein the hydrogenating catalyst consistsessentially of the oxides of nickel, cobalt and molybdenum.

9. A process for hydrocracking heavy petroleum hydrocarbons containingsulfur asphaltic and metalliferous compounds as contaminants, containingsubstantial amounts of hydrocarbon components boiling above 300 F., andcontaining residual materials, which process comprises contacting thehydrocarbons with hydrogen at a temperature from about 750 to about 900F., a pressure from -about 1500 to about 3000 p.s.i., a space velocityfrom about 0:1, to about 5.0 volumes of heavy hydrocarbon per volume ofcatalyst per hour and a hydrogen consumption rate from about 6 to about40 mols of hydrogen per atom of sulfur removed from the heavyhydrocarbons in the presence of a catalyst comprising essentially aminor amount of a hydrogenating catalyst composited with a major amountof an activated alumina having less than '5 'percent'of its pore volumethat is in the form of pores having a radius of 0 to 300 A. in poreslarger than 100 A. radius and having less than percent of said porevolume larger than 80 A. radius prepared by treating a substance whichis predominantly composed of a crystalline alumina hydrate containingfrom 1.2 to 2.6 mols of water of hydration and which is substantiallyfree of alumina monohydrate and alumina trihydrate, said alumina hydratebeing prepared by precipitation from a solution of an aluminum compoundat a pH between about 7 and 12, and drying to the above specified waterof hydration content prior to substantial transformation to an aluminahydrate having a higher or lower water of hydration content, saidtreating comprising hydrothermally treating the dried alumina hydrate byheating it in the presence of water at a temperature sufficient tovaporize the water under autogenous pressure, whereby the aluminahydrate is converted substantially to a monohydrate, and drying andcalcining the hydrothermally treated alumina hydrate.

10. The process of claim 9 wherein the contacting temperature is fromabout 780 to about 875 E, the pressure is from about 2000 to about 2500p.s.i., the space Velocity is from about 0.2 to about 2.0 volumes ofheavy pounds as contaminants, containing substantial amounts ofhydrocarbon components boiling'above 300 F., containing residualmaterials, and containing harmful amounts of sulfur compounds, whichprocess comprises contacting the hydrocarbons with hydrogen at aninitial temperature from about 700 to about 800 F., gradually increasingthe temperature at a rate suflicient to maintain the sulfur content ofthe product below a predetermined level and terminating the contactingwhen a temperature in the range from about 775 to about 875 F. has beenreached, while maintaining a pressure from about 300 to about 2000p.s.i., a space velocity from about. 0.1 to about 10.0 volumes of heavyhydrocarbon per volume of catalyst per hour and a hydrogen consumptionrate from about 1 to about 5 mols of hydrogen per atom of sulfur removedfrom the heavy hydrocarbons, the contacting being conducted in thepresence of a catalyst comprising essentially a minor amount of ahydrogenating catalyst composited with a major amount of an activatedalumina having less than 5 percent of its pore volume that is in theform of pores having a radius of 0 to 300 A. in pores larger than 100 A.radius and having less than 10 percent of said pore volume in poreslarger than 80 A. radius prepared by treating a substance which ispredominantly composed of a crystalline alumina hydrate conturesuificient to vaporize the water under autogenous pressure, whereby thealumina hydrate'is convertedsubstantially to a monohydrate, and dryingand calcining the hydrothermally treated alumina hydrate.

. 14. The process of claim 13 wherein the initial temperature is fromabout 750 to about 775 F., the contacting is terminated when atemperature in the range from about 800 to about *850 F. is reached, thepressure is from about 1000 to about 1500 p.s.i., the spacevelocity isfrom about 0.2 to about 3.0 volumes of heavy hydrocarbon per volume ofcatalyst per hour and the hydrogen consumption rate is from about 2 toabout 5 mols of hydrogen per atom of sulfur removed from the heavyhydrocarbons.

15. The process of claim 13 wherein the hydrogenating catalyst isselected from the group consisting of Group VI metals, Group VIIImetals, their oxides and sulfides.

16. The process of claim 13 wherein the hydrogenating catalyst consistsessentially of the oxides of nickel, cobalt and molybdenum.

17. A process for hydrocracking heavy petroleum hy drocarbons.containing sulfur, asphaltic and metalliferous compounds ascontaminants, containing substantial anten a o hydrocarbon mm gv aboveF., and containing residual materials, which process com prisescontacting the hydrocarbons with hydrogen at an initial temperature fromabout 750 to about 850 F., gradually increasing the temperature at arate sufficient to maintain a predetermined rate of conversion andtermimating the contacting when a temperature in the range from about810 to about 900 -F. has been reached, while maintaining a pressure fromabout 1500 to about 3000 p.s.i., a space velocity from about 0.1 toabout 5.0 volumes of heavy hydrocarbon per volume of catalyst per hourand a hydrogen consumption rate from about 6 to about 40 mols ofhydrogen per atom of sulfur removed from the heavy hydrocarbons, thecontacting being conducted in the presence of a catalyst comprisingessentially a minor amount of a hydrogenating catalyst composited with amajor amount of an activated alumina having less than 5 percent of itspore volume that is in the form of pores having a radius of to 300 A. inpores larger than 100 A. radius and having less than 10 percent of saidpore volume in pores larger than 80 A. radius prepared by treating asubstance which is predominantly composed of a crystalline aluminahydrate containing from 1.2 to 2.6 mols of water of hydration and whichis substantially free of alumina monohydrate and alumina trihydrate,said alumina hydrate being prepared by precipitation from a solution ofan aluminum compound at a pH between about 7 and 12, and drying to theabove specified water of hydration content prior to substantialtransformation to an alumina hydrate having a higher or lower water ofhydration content, said treating comprising hydrothermally treating thedried alumina hydrate by heating it in the presence of water at atemperature suflicient to vaporize the water under autogenous pressure,whereby the alumina hydrate is converted substantially to a monohydrate,and drying and calcining the hydrothermally treated alumina hydrate.

18. The process of claim 17 wherein the initial temperature is fromabout 780 to about 810 F., the contacting is terminated when atemperature in the range from about 840" to about 875 F. is reached, thepressure is from about 2000 to about 2500 p.s.i., the space velocity isfrom about 0.2 to about 20 volumes of heavy hydrocarbon per volume ofcatalyst per hour and the hydrogen consumption rate is from about 6 toabout 20 mols of hydrogen per atom of sulfur removed from the heavyhydrocarbons.

19. The process of claim 17 wherein the hydrogenating catalyst isselected from the group consisting of Group VI metals, Group VIIImetals, their oxides and sulfides.

20. The process of claim 17 wherein the hydrogenating catalyst consistsessentially of the oxides of nickel, cobalt and molybdenum.

References Cited DELBERT E. GANTZ, Primary Examiner.

SAMUEL P. JONES, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,340,180 September 5 1967 Harold Beuther et a1.

d that error appears in the above numbered pat- It is hereby certifie idLetters Patent should read as ent requiring correction and that the sacorrected below.

Column 1, line 12, for "derviatives" read derivatives line 66, for"metalliferrous" read metalliferous column 2, line 19, for "radium" readradius column 5, lines 9 and 10 for "exten" read extent line 40 fortemployment read employment column 7, line 73, for "deculfurization"readl-fidesulfurization column 10, line 32, for "11.6" read 1 Signed andsealed this 20th day of August 1968.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer

1. A PROCESS FOR HYDROGEN TREATMENT OF HEAVY PETROLEUM HYDROCARBONCONTAINING SULFUR, ASPHALTIC AND METALLIFEROUS COMPOUNDS ASCONTAMINANTS, CONTAINING SUBSTANTIAL AMOUNTS OF HYDROCARBON COMPONENTSBOILING ABOVE 300*F. AND CONTAINING RESIDUAL MATERIALS, WHICH PROCESSCOMPRISES CONTACTING THE HYDROCARBONS WITH HYDROGEN AT A PRESSURE FROMABOUT 300 TO ABOUT 3000 P.S.I., A SPACE VELOCITY FROM ABOUT 0.1 TO ABOUT10.0 VOLUMES OF HEAVY HYDROCARBON PER VOLUME OF CATALYST PER HOUR, AHYDROGEN CONSUMPTION RATE FROM ABOUT 1 TO ABOUT 40 MOLS OF HYDROGEN PERATOM OF SULFUR REMOVED FROM THE HEAVY HYDROCARBONS AND AT A TEMPERATUREFROM ABOUT 700 TO ABOUT 900*F. IN THE PRESENCE OF A CATALYST COMPRISINGESSENTIALLY A MINOR AMOUNT OF A HYDROGENATING CATALYST COMPOSITED WITH AMAJOR AMOUNT OF AN ACTIVATED ALUMINA HAVING LESS THAN 5 PERCENT OF ITSPORE VOLUME THAT IS IN THE FORM OF PORES HAVING A RADIUS OF 0 TO 300 A.IN PORES LARGER THAN 100 A. RADIUS AND HAVING LESS THAN 10 PERCENT OFSAID PORE VOLUME IN PRES LARGER THAN 80 A. RADIUS WHICH ALUMINA ISPREPARED BY TREATING A SUBSTANCE WHICH IS PREDOMINANTLY COMPOSED OF ACRYSTALLINE ALUMINA HYDRATE CONTAINING FROM 1.2 TO 2.6 MOLS OF WATER OFHYDRATION AND WHICH IS SUBSTANTIALLY FREE OF ALUMINA MONOHYDRATE ANDALUMINA TRIHYDRATE, SAID ALUMINA HYDRATE BEING PREPARED BY PRECIPITATIONFROM A SOLUTION OF AN ALUMINUM COMPOUND AT A PH BETWEEN 7 AND 12, ANDDRYING TO THE ABOVE SPECIFIED WATER OF HYDRATION CONTENT PRIOR TOSUBSTANTIAL TRANSFORMATION TO AN ALUMINA HYDRATE HAVING A HIGHER ORLOWER WATER OF HYDRATION CONTENT, SAID TREATING COMPRISINGHYDROTHERMALLY TREATING THE DRIED ALUMINA HYDRATE BY HEATING IT IN THEPRESENCE OF WATER AT A TEMPERATURE SUFFICIENT TO VAPORIZE THE WATERUNDER AUTOGENOUS PRESSURE, WHEREBY THE ALUMINA HYDRATE IS CONVERTEDSUBSTANTIALLY TO A MONOHYDRATE AND DRYING AND CALCINING THEHYDROTHERMALLY TREATED ALUMINA HYDRATE.